This study applied Near Infrared (NIR) and Mid Infrared (MIR) Spectroscopy combined with chemometrics to detect and quantify adulteration in cupuaçu pulp. A total of 66 authentic samples, 198 adulterated with sucrose solution (15, 30, and 45 % w/w), and 25 commercial samples were analyzed. Classification models showed high accuracy, sensitivity, and specificity, with MIR achieving 100 % accuracy in validation. For quantification, MIR performed best, with an R-value of 0.96. Adulteration was detected in over 50 % of commercial samples, with levels ranging from 15.28 % to 34.45 %. The results confirm that NIR and MIR are effective tools for identifying and quantifying cupuaçu pulp adulteration, demonstrating their potential for quality control applications.